mirror of https://github.com/lefticus/6502-cpp.git
131 lines
2.9 KiB
C++
131 lines
2.9 KiB
C++
#include <array>
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#include <chrono>
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#include <cstdint>
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#include <cstring>
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#include <string_view>
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enum Colors : uint8_t { WHITE = 0x01 };
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inline volatile uint8_t &memory_loc(const uint16_t loc) {
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return *reinterpret_cast<volatile uint8_t *>(loc);
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}
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inline void poke(const uint16_t loc, const uint8_t value) {
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memory_loc(loc) = value;
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}
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inline std::uint8_t peek(const std::uint16_t loc) { return memory_loc(loc); }
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inline void decrement_border_color() { --memory_loc(0xd020); }
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inline void increment_border_color() { ++memory_loc(0xd020); }
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inline bool joystick_down() {
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uint8_t joystick_state = memory_loc(0xDC00);
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return (joystick_state & 2) == 0;
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}
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void use_data(std::array<char, 1024> &data);
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inline void puts(uint8_t x, uint8_t y, std::string_view str) {
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const auto start = 0x400 + (y * 40 + x);
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std::memcpy(const_cast<uint8_t *>(&memory_loc(start)), str.data(),
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str.size());
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}
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inline void putc(uint8_t x, uint8_t y, uint8_t c) {
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const auto start = 0x400 + (y * 40 + x);
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poke(start, c);
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}
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inline void put_hex(uint8_t x, uint8_t y, uint8_t value) {
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const auto put_nibble = [](auto x, auto y, uint8_t nibble) {
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if (nibble <= 9) {
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putc(x, y, nibble + 48);
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} else {
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putc(x, y, nibble - 9);
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}
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};
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put_nibble(x + 1, y, 0xF & value);
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put_nibble(x, y, 0xF & (value >> 4));
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}
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inline void put_hex(uint8_t x, uint8_t y, uint16_t value) {
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put_hex(x+2,y, static_cast<std::uint8_t>(0xFF & value));
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put_hex(x,y, static_cast<std::uint8_t>(0xFF & (value >> 8)));
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}
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struct Clock {
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using milliseconds = std::chrono::duration<std::uint16_t, std::milli>;
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// return elapsed time since last restart
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[[nodiscard]] milliseconds restart() {
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// stop Timer A
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poke(0xDC0E, 0b00000000);
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// last value
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const auto previous_value = static_cast<std::uint16_t>(
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peek(0xDC04) | (static_cast<uint16_t>(peek(0xDC05)) << 8));
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// reset timer
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poke(0xDC04, 0xFF);
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poke(0xDC05, 0xFF);
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// restart timer A
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poke(0xDC0E, 0b00010001);
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return milliseconds{0xFFFF - previous_value};
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}
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Clock() { [[maybe_unused]] const auto value = restart(); }
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};
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int main() {
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// static constexpr std::array<std::uint8_t, 1000> data{0};
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// std::memcpy(const_cast<uint8_t*>(&memory_loc(0x400)), data.data(),
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// data.size());
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/*
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puts(5, 5, "hello world");
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puts(10, 10, "hellooooo world");
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*/
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Clock game_clock{};
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std::uint16_t counter = 0;
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std::uint8_t y = 15;
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while (true) {
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const auto us_elapsed = game_clock.restart().count();
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put_hex(5, y, us_elapsed);
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put_hex(11, y, counter);
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if (y++ == 20) {
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y = 15;
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}
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++counter;
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increment_border_color();
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}
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/*
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const auto background_color = [](Colors col) {
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memory_loc(0xd021) = static_cast<uint8_t>(col);
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};
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background_color(Colors::WHITE);
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while(true) {
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if (joystick_down()) {
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increment_border_color();
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} else {
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decrement_border_color();
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}
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}
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*/
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}
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